In order to benefit from drafting, you've got to be in the drafting
bubble behind the cyclist immediately in front of you. And in a
crosswind the bubble will NOT be directly behind the rider in front but
will be some angle away from them. The effectiveness of this bubble
decreases with the distance, being the greatest if you draft closely
and falling off until there is minimal benefit at 5 or 6 feet. The
important fact is that you will get some benefit 3, or even 4 feet,
back - and it's a lot safer than being directly on the rear wheel of
the rider in front of you.

The rider being drafted also gains a slight advantage. This is
explained by the fact that the low pressure behind the lead rider is
increased in a pace line, giving the leader a slight "nudge" due to the
pressure differential between the high pressure ahead and the low
pressure behind. This is why a NASCAR racing car will go 1-2 mph faster
when being drafted.


From:

http://northwesthandcycleclub.org/Fr...=1152136001681

That was just a quick find on the web but you can find the problem in
any aero/fluid dynamics physics book.

Regards
Chris